What Is Open-Angle Glaucoma?

Open-angle glaucoma occurs when pressure builds up inside the eye due to improper drainage of intraocular fluid. Over time, this pressure damages the optic nerve, which is essential for sending visual information from the eye to the brain.

Unlike angle-closure glaucoma, POAG develops slowly and painlessly, often without noticeable symptoms until significant vision loss has already occurred.

Signs and Symptoms

Because open-angle glaucoma affects peripheral (side) vision first, most people remain unaware of the condition in its early stages. As the disease progresses, symptoms may include:

• Loss of peripheral vision
• Tunnel vision in advanced stages
• Blind spots in the field of vision
• Frequent changes in eyeglass prescriptions

Unfortunately, central vision is only affected in the late stages, which is why many patients do not realise there’s an issue until extensive damage has occurred.

Who’s at Risk?

Everyone is at risk, but the following factors significantly increase the likelihood of developing POAG:

• Age: People over 60
• Family history of glaucoma
• African or Latino descent
• High eye pressure (intraocular pressure or IOP)
• Thin corneas
• Medical conditions such as diabetes, hypertension, and myopia
• Use of corticosteroid medications
• Previous eye injuries

Because the condition can be hereditary and progresses without pain, it’s essential to schedule eye exams at least annually—especially if you’re in a high-risk category.

Diagnosis and Monitoring

Detection of open-angle glaucoma requires a comprehensive eye examination, including:

• Tonometry to measure intraocular pressure
• Ophthalmoscopy to inspect the optic nerve
• Visual field testing to detect peripheral vision loss
• Pachymetry to measure corneal thickness

Monitoring these values over time helps eye care professionals determine disease progression and effectiveness of treatment.

Treatment Options

While there’s currently no cure for glaucoma, the damage can be significantly slowed or halted with appropriate intervention.

The main goal of treatment: Lower the intraocular pressure (IOP)

1. Medication (Eye Drops)

• Prostaglandin analogues: e.g., latanoprost, travoprost – often first-line treatment due to once-daily dosage and effectiveness
• Beta-blockers: e.g., timolol – useful in younger patients or unilateral glaucoma
• Alpha agonists, carbonic anhydrase inhibitors, and miotics are additional or adjunctive options

2. Laser Therapy

• Selective Laser Trabeculoplasty (SLT) is commonly used to enhance fluid drainage

3. Surgery

• In severe cases, surgical procedures like trabeculectomy or drainage implants may be considered

The Importance of Regular Eye Exams

Glaucoma doesn’t wait for symptoms to become obvious—it quietly progresses until the damage is permanent. That’s why routine eye check-ups, especially after age 40 or if you’re at high risk, are non-negotiable in preserving your sight.

“Vision lost to glaucoma cannot be restored, but early detection and consistent treatment can save what remains.”

Diabetic Retinopathy (DR) is a serious eye condition caused by high blood sugar levels damaging the tiny blood vessels in the retina, the light-sensitive tissue at the back of the eye. It affects people with Type 1 and Type 2 diabetes, often without noticeable symptoms until vision is compromised.

It’s one of the leading causes of blindness globally, especially among adults in their most productive years. Early detection through regular eye exams is essential for preventing permanent vision loss.

Stages of Diabetic Retinopathy

DR progresses through two major forms and four defined stages:

Non-Proliferative Diabetic Retinopathy (NPDR) – Early Stage

1. Mild NPDR: Microaneurysms (tiny balloon-like swellings in blood vessels) begin to form.
2. Moderate NPDR: Vessels swell and distort, impairing blood flow.
3. Severe NPDR: Widespread vessel blockage leads to areas of the retina being deprived of oxygen, triggering new vessel growth signals.

Proliferative Diabetic Retinopathy (PDR) – Advanced Stage

4. PDR: Fragile, abnormal new blood vessels form (neovascularisation), often leaking into the vitreous. This can cause floaters, blurred vision, severe haemorrhaging, or even retinal detachment and vision loss.

In some cases, patients with PDR may only see shadows or light-dark contrast in affected eyes.

Signs and Symptoms

Early stages may be asymptomatic, but as DR progresses, symptoms include:

• Blurred or distorted vision
• Floaters (dark spots or strings in vision)
• Difficulty seeing at night
• Dark or empty areas in central vision
• Fluctuating vision
• Sudden vision loss (in cases of vitreous haemorrhage)

Causes and Risk Factors

The underlying cause is chronic high blood glucose damaging retinal blood vessels. As blood vessels leak, swell, or become blocked, retinal tissues become oxygen-deprived, causing irreversible damage.

Key risk factors include:

• Duration of diabetes: Risk increases after 10–20 years of the condition.
• Poor blood sugar control (high HbA1c levels)
• High blood pressure and cholesterol
• Pregnancy (especially gestational diabetes)
• Hispanic and African heritage
• Protein in urine (marker of kidney and retinal damage)
• Smoking

Even rapid glucose correction in long-term diabetics can trigger temporary worsening of DR.

Diagnosis and Monitoring

A comprehensive dilated eye exam is the gold standard for detecting DR. Retinal photography, OCT scanning, and fluorescein angiography may also be used to assess the retina’s condition.

Regular screenings are critical—especially if you’re diabetic, pregnant, or have been diagnosed with DR before.

Treatment Options

While there is no cure, treatment can slow progression and preserve vision.

Laser Therapy (Photocoagulation)

• Used in PDR to seal leaking vessels and prevent further abnormal growth.
• Panretinal photocoagulation (PRP) targets peripheral retina to preserve central vision.

Injections

• Anti-VEGF medications like Lucentis, Eylea, and Avastin reduce vessel growth and leakage.
• Steroid injections for persistent macular swelling (DME).

Vitrectomy Surgery

• Performed when there’s significant vitreous haemorrhage or retinal detachment.
• Involves removing the gel inside the eye and replacing it to restore or maintain vision.

Systemic Management

• Controlling blood sugar, blood pressure, and cholesterol significantly reduces the risk.
• HbA1c levels should be maintained at 6–7% as per international guidelines.

Patient education and lifestyle management play a critical role in treatment success.

Have diabetes? Don’t wait for symptoms.

Schedule your retinal screening with Davida van der Merwe Optometrist today to detect diabetic retinopathy early and protect your vision for years to come.

Hypertensive Retinopathy (HR) is a condition where high blood pressure damages the small blood vessels in the retina, the light-sensitive tissue at the back of the eye. Over time, elevated blood pressure can cause these vessels to narrow, thicken, leak fluid, or even rupture—leading to swelling, haemorrhages, and potential vision loss.

In some cases, an eye exam may be the first indication of undiagnosed hypertension, making your optometrist a critical part of systemic disease detection.

Stages of Hypertensive Retinopathy

The Keith-Wagener-Barker classification outlines four stages of HR:

• Stage 1: Mild narrowing of retinal arteries. Often seen in older adults.
• Stage 2: Moderate vessel narrowing and arteriovenous nicking (veins compressed at crossings).
• Stage 3: Signs from Stage 1 & 2 plus cotton-wool spots, haemorrhages, and lipid exudates.
• Stage 4: Advanced retinal damage including optic nerve swelling (papilledema) and macular star formation. This is known as malignant hypertension and is a medical emergency.

Routine eye exams allow early detection and prevent progression to these severe stages.

Signs and Symptoms

Most people don’t experience symptoms in the early stages of HR. However, as the condition worsens, symptoms may include:

• Blurred or reduced vision
• Eye pain or headaches (in severe hypertension)
• Dark or shadowy spots in vision
• Visual disturbances such as flashing lights or distortion
• Signs during eye exam:
  • Tortuous or twisted vessels
  • Retinal bleeding
  • Cotton wool spots (indicative of poor oxygen supply)
  • Swollen optic nerve (papilledema)
  • Macular edema or retinal detachment

Causes and Risk Factors

The primary cause of Hypertensive Retinopathy is uncontrolled or long-term high blood pressure. As pressure increases, retinal vessels become fragile and damaged.

Common risk factors include:

• Chronic hypertension
• Poorly managed diabetes or cholesterol
• Smoking and excessive alcohol intake
• Obesity and inactivity
• High-salt diets
• Genetic predisposition
• Stress or anxiety-related blood pressure spikes
• Certain ethnic groups with higher hypertension rates

Malignant hypertension (BP ≥180/120 mmHg) can lead to sight-threatening emergencies, including retinal detachment and permanent nerve damage.

Diagnosis and Eye Exam Findings

Optometrists use fundus examinations, optical coherence tomography (OCT), and retinal photography to assess for signs of HR. Key diagnostic indicators include:

• Arterial narrowing
• Arteriovenous nicking
• Flame-shaped haemorrhages
• Macular star pattern from lipid leakage
• Cotton-wool spots
• Swelling of the optic disc (papilledema)

Differentiation from other retinal diseases like diabetic retinopathy is vital to accurate diagnosis and appropriate management.

Treatment Options

Hypertensive Retinopathy itself has no direct cure—treatment focuses on controlling blood pressure and preventing further eye damage.

For Stage 1 & 2:

• Regular blood pressure management
• Lifestyle changes (diet, exercise, stress reduction)
• Annual dilated eye exams

For Stage 3 & 4:

• Urgent medical treatment of systemic hypertension
• Intravitreal injections for macular edema
• Surgical intervention for retinal detachment
• Co-management with cardiologists and general practitioners

If caught early, HR is preventable and manageable. Delayed treatment in stages 3 or 4 may result in permanent vision impairment or other systemic complications like stroke or heart failure.

Macular Degeneration (MD) is a common eye disorder that affects the macula, the part of the retina responsible for sharp, central vision. As the tissue deteriorates, your ability to see fine details, such as faces, print, or road signs, is compromised—though your peripheral vision remains intact, meaning the condition does not lead to total blindness.

There are two main forms of the condition:

• Dry Macular Degeneration (slow-progressing; 85–90% of cases)
• Wet Macular Degeneration (faster and more severe)

Early detection and monitoring are essential for preserving your vision. Annual eye exams are strongly advised, especially if you are over 60 or at increased risk.

Dry vs Wet Macular Degeneration

Dry AMD

Occurs due to the gradual thinning of macular tissue and buildup of drusen (yellow deposits). It develops slowly and may cause:

• Mild central vision loss
• Difficulty reading, recognising faces, or driving
• Blurred or distorted images

Wet AMD

Caused by abnormal blood vessels growing under the retina, which can leak fluid and blood. This leads to:

• Sudden, severe central vision loss
• Dark spots, distortion, or rapid deterioration
• Scar tissue forming in the retina

Although less common, wet AMD requires urgent attention.

Symptoms of Macular Degeneration

Patients with MD may experience:

• Blurry or fuzzy central vision
• Distorted images – straight lines may appear wavy
• Difficulty recognising faces
• Shadows or dark patches in the centre of vision
• Poor colour contrast
• Slow visual recovery after bright light exposure
• Visual acuity drops (e.g. from 20/20 to 20/80)

An Amsler grid test is often used to detect changes early. Patients may notice missing lines or blank spots.

Causes and Risk Factors

Although the exact cause remains unclear, several genetic and lifestyle factors contribute to the development of MD.

Key risk factors include:

• Age (especially 60+)
• Family history of MD
• Smoking (a major contributor to vision loss)
• High blood pressure and cardiovascular disease
• Obesity and physical inactivity
• Excessive sunlight exposure
• Poor nutrition (low in leafy greens, omega-3s, and antioxidants)
• Certain medications, including some anti-malarials and antipsychotics

Diagnosis and Monitoring

Macular Degeneration is diagnosed through:

• Dilated eye exams
• Retinal imaging (OCT and fundus photography)
• Amsler grid testing (to detect visual distortion)

Once diagnosed, it is crucial to monitor your vision regularly and report any sudden changes.

Treatment Options

While there is no cure, several treatment strategies can help slow progression and support functional vision.

For Dry AMD:

• Nutritional supplements (lutein, zeaxanthin, zinc, and omega-3s)
• Healthy diet with cold-water fish and leafy greens
• UV-blocking sunglasses
• Lifestyle changes: quit smoking, manage blood pressure

For Wet AMD:

• Anti-VEGF injections (e.g. Lucentis, Eylea, Macugen) – reduce vessel growth and leakage
• Photodynamic therapy (PDT) – seals leaky vessels using light and medication
• Low vision aids – magnifiers, reading devices, and high-contrast lighting

Your optometrist will help detect changes early and refer you to a retinal specialist if required.

Seeing distortions, dark patches, or struggling with detail?

Book a comprehensive retinal screening at Davida van der Merwe Optometrist to detect macular degeneration early and safeguard your vision.

The month of February is Age Related Macular Degeneration (AMD) Awareness Month. A period, where eyecare is of the utmost importance.

What is Age Related Macular Degeneration?

Age related macular degeneration or AMD is a leading cause of blindness. It’s a painless and usually progressive condition of the retina, which is the inner layer of the eye.

What makes this condition so serious, is that there is no treatment for the most common (dry) form.

Furthermore, early signs are easy to miss, which makes regular examinations by your optometrist vital.

At Davida van der Merwe Optometrist, Davida will examine your eyes for AMD by using a microscope, a retinal camera and an ocular coherence tomographer (OCT) to view, take photographs and scan the back of your eye.

Who is at risk for AMD?

The risk of AMD is higher if you are female, over 40 or if there is a history of AMD in your family.

“AMD is irreversible, so if any of these apply to you, please call 034 312 4602 for a consultation,” says Davida van der Merwe.

Can we prevent AMD?

A person can reduce the risk of developing AMD by making healthy lifestyle choices. These choices include:

Stop smoking

Smokers have a four times higher risk than non-smokers to get AMD. Even past smokers have double the risk, which improves over time.

Healthy diet

Eat dark green vegetables, such as spinach and broccoli. Eating these vegetables raw will be even better for your health.

Also add colourful fruits and vegetables to your diet, as they are rich in carotenoids. Carotenoids help maintain the pigment in the macula.

It is also important to limit your intake of refined carbohydrates.

Supplements

Ask your optometrist about AMD-specific multivitamins and minerals. Extensive research has identified the best antioxidant combination for those at risk for AMD.

Vitamins A, C and E, zinc and selenium, and lutein and zeaxanthin should all be included, although it must be in the correct dose.

Check which option is best for you before you start taking any supplements.

Exercise
Older adults who lead an active lifestyle are less likely to get AMD.

Try this macula-friendly salad recipe: 

• Break or cut a head of broccoli into small florets.
• Cover in a dressing made up of equal quantities of mayonnaise and low fat yoghurt.
• Just before serving, sprinkle over: 
  1 c Cranberries
  1 c Crispy bacon bits (so the men in your house will eat it)
  1/2 c Toasted slivered almonds

The broccoli is raw, so it’s a great source of fibre and it’s packed with vitamins A and C. There’s fibre in the almonds too, as well as vitamin E, magnesium and a few healthy types of fat. The yoghurt delivers potassium, protein and calcium and the cranberries are a fantastic source of vitamin C.

Did you know?

Macula is the Latin word for a spot or a stain. The macula in the eye is seen as a slightly darker area of the retina.

“During your examination, we will point it out to you on your photographs and scans,” says Davida van der Merwe.

Diabetes mellitus, commonly known as diabetes, is a metabolic disease which results in high blood sugar.

If you, or someone close to you has diabetes, you will know that diabetes is one of the biggest causes of vision loss.

As diabetes affects both young and old, Davida van der Merwe Optometrist answers some of your questions pertaining to the disease and how it affects your sight.

How does diabetes affect my eyes?

Diabetes causes problems with blood flow and blood vessels inside the eye. The blood vessels can weaken, leak or bleed, affecting the retina at the back of the eye. Damage to the retina is called retinopathy.

Does it happen to everyone with diabetes? 

Leaking can happen irrespective of the fact that your diabetes is well controlled, or whether you have Type 1 or Type 2 diabetes. But, when the diabetes is not well controlled, you’re more likely to have leaks and bleeding.

What happens is that new blood vessels start to grow, trying to compensate for oxygen shortages caused by damage in the original blood vessels.

New blood vessels are called neovascularisation. These break and bleed even more easily so seeing them is a bad sign.

How can you see diabetic retinopathy? 

We routinely examine the retina of every patient. But if we know you are diabetic, we will focus on specific areas which are more at risk.

Fluid leaking into the macula can dramatically affect vision, because the macula is our area of clearest, central vision. We may photograph or scan your retina, so we can keep accurate records and compare tiny leaks over a few weeks or months.

Improving diabetes control – reducing your blood sugar – can improve the retinopathy. We will show you your photographs and scans and explain what we’re seeing.

The same type of leaking that results in retinopathy can happen in your kidneys as well, so it’s helpful if you allow us to share your results with your medical doctor.

How will diabetes change my vision? 

Diabetes can cause changes in vision from damage to the blood vessels, or changes to the lens of the eye.

As the lens swells and shrinks back, your glasses prescription can change with it. If your diabetes is newly diagnosed, or if your medication has changed, your vision and your prescription is likely to fluctuate.

We may delay making your final glasses, until we can confirm that your levels have stabilised.

What else should you be aware of? 

The lens in the eye, which eventually changes to become a cataract, may do so more quickly if you have diabetes.

We’ll check this progress at each visit and let you know when it’s time to refer you to the surgeon to discuss cataract surgery.

We will also discuss the frequency of your follow-up visits, depending on our findings during the examination.

Patients with well-controlled diabetes, should have a routine examination every year. If we want to follow your progress more closely, we may ask you to come in sooner.

Leaking at the macula can happen at any stage of diabetes, in Type 1 and Type 2. So, patients should come in between scheduled visits if they feel their vision may be changing.

With World Diabetes Day falling on November, if you, or someone close to you is diabetic, ensure you or they have a diabetic eye examination.

We are here to answer your questions on diabetes and how it affects your eyes.